PROJECT SUMMARY Core C provides access to specialized professional and technical pathology services and genomic services that are essential to the success of the Program. It does so by carrying out 3 overarching aims that support all three P01 Projects: 1) provide pathology expertise needed for classification of primary human PTCLs and PDX and murine PTCL models; 2) perform standard and novel in situ tests for biomarkers relevant to understanding PTCL pathophysiology and its response and resistance to novel therapies; and 3) perform targeted exome sequencing of a large cohort of well-characterized human PTCLs. The Core delivers these services at two performance sites, one in Boston led by Jon Aster, which will deliver services supporting Aims 1 and 2, and the second in North Carolina led by Sandeep Dave, which will deliver services supporting Aims 1 and 3. Delivery of Aim 1 services relies on the Core's co-leader, Dr. Jon Aster, who is a practicing academic hematopathologist with >25 years of experience with human and murine hematopathology, and is supplemented by additional expertise in Project 1 (John Chan) and access to the Hematologic Malignancies Research Consortium, which includes >25 institutions and has accrued over 1800 cases of T cell lymphomas, a majority with paired normal tissue. Aim 2 services will be provided in Boston include standard histology and immunohistology services and innovative, multiparametric immunofluorescence staining platforms, the Perkin- Elmer Vectra platform and CyCIF is an iterative imaging platform that allows for evaluation of >50 different markers on single FFPE slides. Aim 3 services are delivered at the North Carolina performance site by performing targeted exome sequencing on 410 genes that are frequently mutated in lymphoma, initially using DNA prepared from a cohort of 1833 PTCLs and paired normal tissue controls.